Many modern computing devices are capable of executing multiple operating systems simultaneously. Typical computing devices may use virtualization to execute multiple guest operating systems under the control of a virtual machine monitor and/or hypervisor. Virtualization solutions typically require execution of multiple complete operating systems and may require potentially expensive virtualization of hardware resources. Thus, virtualization solutions may be relatively resource-intensive, particularly for resource-constrained computing devices such as smart phones and other mobile devices. Techniques for concurrent isolated execution of application routines using relatively minimal processing and storage resources are described in International Application Publication Number WO 2015/089730, by Shoumeng Yan, and entitled Techniques for Portable Computing Device Virtualization. In the system described by the Yan reference, peripheral device I/O data is discarded for background instances.